It’s easy being green: With caterpillar populations crashing, once-bare trees are in full bloom

By Jane Mackay

Friday

Jun 22, 2007 at 12:01 AMJun 22, 2007 at 10:17 PM

Ireland should look this green. After several years of devastating caterpillar infestations that left trees as bare in spring as in mid-winter, the South Shore is lush with foliage.

Ireland should look this green. After several years of devastating caterpillar infestations that left trees as bare in spring as in mid-winter, the South Shore is lush with foliage.

The populations are way down this year for four species of caterpillar that typically spend spring munching leaves and buds, said Deborah Swanson, a horticulturist with the Plymouth County/UMass Extension Service.

Gypsy moth and tent moth caterpillar populations crashed thanks to fungus that thrived in the cool, wet weather of the past two springs.

Numbers of the eastern tent caterpillar, which is recognizable from the tents they build in the crotches of cherry, crab apple and apple trees, are also down.

Swanson said no one knows where the winter moth caterpillars went.

Consistent spraying by towns and private contractors, and the release of a parasitic fly that dines on winter moth larvae, have gone a long way toward controlling caterpillar populations, Swanson said.

‘‘People should not stop spraying, because the caterpillars could come back right away,’’ she said.

For people whose trees were defoliated in prior years, it’s important to make sure that the trees get at least an inch of water a week to help them rebuild their root systems, Swanson said.

Otherwise, enjoy the scenery.

‘‘Trees in south Plymouth County look the best they have in several years,’’ she said.